New BytesFormatter to unify all bytes formats

/*

 * Copyright (C) 2025 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.android.settingslib.spaprivileged.framework.common

import android.content.Context

import android.content.res.Resources

import android.icu.text.DecimalFormat

import android.icu.text.MeasureFormat

import android.icu.text.NumberFormat

import android.icu.text.UnicodeSet

import android.icu.text.UnicodeSetSpanner

import android.icu.util.Measure

import android.text.format.Formatter

import android.text.format.Formatter.RoundedBytesResult

import java.math.BigDecimal

class BytesFormatter(resources: Resources) {

    enum class UseCase(val flag: Int) {

        FileSize(Formatter.FLAG_SI_UNITS),

        DataUsage(Formatter.FLAG_IEC_UNITS),

    }

    data class Result(val number: String, val units: String)

    constructor(context: Context) : this(context.resources)

    private val locale = resources.configuration.locales[0]

    fun format(bytes: Long, useCase: UseCase): String {

        val rounded = RoundedBytesResult.roundBytes(bytes, useCase.flag)

        val numberFormatter = getNumberFormatter(rounded.fractionDigits)

        return numberFormatter.formatRoundedBytesResult(rounded)

    }

    fun formatWithUnits(bytes: Long, useCase: UseCase): Result {

        val rounded = RoundedBytesResult.roundBytes(bytes, useCase.flag)

        val numberFormatter = getNumberFormatter(rounded.fractionDigits)

        val formattedString = numberFormatter.formatRoundedBytesResult(rounded)

        val formattedNumber = numberFormatter.format(rounded.value)

        return Result(

            number = formattedNumber,

            units = formattedString.removeFirst(formattedNumber),

        )

    }

    private fun NumberFormat.formatRoundedBytesResult(rounded: RoundedBytesResult): String {

        val measureFormatter =

            MeasureFormat.getInstance(locale, MeasureFormat.FormatWidth.SHORT, this)

        return measureFormatter.format(Measure(rounded.value, rounded.units))

    }

    private fun getNumberFormatter(fractionDigits: Int) =

        NumberFormat.getInstance(locale).apply {

            minimumFractionDigits = fractionDigits

            maximumFractionDigits = fractionDigits

            isGroupingUsed = false

            if (this is DecimalFormat) {

                setRoundingMode(BigDecimal.ROUND_HALF_UP)

            }

        }

    private companion object {

        fun String.removeFirst(removed: String): String =

            SPACES_AND_CONTROLS.trim(replaceFirst(removed, "")).toString()

        val SPACES_AND_CONTROLS = UnicodeSetSpanner(UnicodeSet("[[:Zs:][:Cf:]]").freeze())

    }

}

/*

 * Copyright (C) 2025 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.android.settingslib.spaprivileged.framework.common

import android.content.Context

import androidx.test.core.app.ApplicationProvider

import androidx.test.ext.junit.runners.AndroidJUnit4

import com.google.common.truth.Truth.assertThat

import org.junit.Test

import org.junit.runner.RunWith

@RunWith(AndroidJUnit4::class)

class BytesFormatterTest {

    private val context: Context = ApplicationProvider.getApplicationContext()

    private val formatter = BytesFormatter(context)

    @Test

    fun `Zero bytes`() {

        // Given a byte value of 0, the formatted output should be "0 byte" for both FileSize

        // and DataUsage UseCases. This verifies special handling of zero values.

        val fileSizeResult = formatter.format(0, BytesFormatter.UseCase.FileSize)

        assertThat(fileSizeResult).isEqualTo("0 byte")

        val dataUsageResult = formatter.format(0, BytesFormatter.UseCase.DataUsage)

        assertThat(dataUsageResult).isEqualTo("0 byte")

    }

    @Test

    fun `Positive bytes`() {

        // Given a positive byte value (e.g., 1000), the formatted output should be correctly

        // displayed with appropriate units (e.g., '1.00 kB') for both UseCases.

        val fileSizeResult = formatter.format(1000, BytesFormatter.UseCase.FileSize)

        assertThat(fileSizeResult).isEqualTo("1.00 kB")

        val dataUsageResult = formatter.format(1024, BytesFormatter.UseCase.DataUsage)

        assertThat(dataUsageResult).isEqualTo("1.00 kB")

    }

    @Test

    fun `Large bytes`() {

        // Given a very large byte value (e.g., Long.MAX_VALUE), the formatted output should be

        // correctly displayed with the largest unit (e.g., 'PB') for both UseCases.

        val fileSizeResult = formatter.format(Long.MAX_VALUE, BytesFormatter.UseCase.FileSize)

        assertThat(fileSizeResult).isEqualTo("9223 PB")

        val dataUsageResult = formatter.format(Long.MAX_VALUE, BytesFormatter.UseCase.DataUsage)

        assertThat(dataUsageResult).isEqualTo("8192 PB")

    }

    @Test

    fun `Bytes requiring rounding`() {

        // Given byte values that require rounding (e.g., 1512), the formatted output should be

        // rounded to the appropriate number of decimal places (e.g., '1.51 kB').

        val fileSizeResult = formatter.format(1512, BytesFormatter.UseCase.FileSize)

        assertThat(fileSizeResult).isEqualTo("1.51 kB")

        val dataUsageResult = formatter.format(1512, BytesFormatter.UseCase.DataUsage)

        assertThat(dataUsageResult).isEqualTo("1.48 kB")

    }

    @Test

    fun `FileSize UseCase`() {

        // When the UseCase is FileSize, the correct units (byte, KB, kB, GB, TB, PB) should

        // be used.

        val values =

            listOf(

                1L,

                1024L,

                1024L * 1024L,

                1024L * 1024L * 1024L,

                1024L * 1024L * 1024L * 1024L,

                1024L * 1024L * 1024L * 1024L * 1024L,

                1024L * 1024L * 1024L * 1024L * 1024L * 1024L,

            )

        val expectedUnits = listOf("byte", "kB", "MB", "GB", "TB", "PB", "PB")

        values.zip(expectedUnits).forEach { (value, expectedUnit) ->

            val result = formatter.format(value, BytesFormatter.UseCase.FileSize)

            assertThat(result).contains(expectedUnit)

        }

    }

    @Test

    fun `DataUsage UseCase`() {

        // When the UseCase is DataUsage, the correct units (byte, kB, MB, GB, TB, PB) should

        // be used.

        val values =

            listOf(

                1L,

                1024L,

                1024L * 1024L,

                1024L * 1024L * 1024L,

                1024L * 1024L * 1024L * 1024L,

                1024L * 1024L * 1024L * 1024L * 1024L,

                1024L * 1024L * 1024L * 1024L * 1024L * 1024L,

            )

        val expectedUnits = listOf("byte", "kB", "MB", "GB", "TB", "PB", "PB")

        values.zip(expectedUnits).forEach { (value, expectedUnit) ->

            val result = formatter.format(value, BytesFormatter.UseCase.DataUsage)

            assertThat(result).contains(expectedUnit)

        }

    }

    @Test

    fun `Fraction digits`() {

        // The number of fraction digits in the output should be correctly determined based on

        // the rounded byte value.

        assertThat(formatter.format(1500, BytesFormatter.UseCase.FileSize)).isEqualTo("1.50 kB")

        assertThat(formatter.format(1050, BytesFormatter.UseCase.FileSize)).isEqualTo("1.05 kB")

        assertThat(formatter.format(999, BytesFormatter.UseCase.FileSize)).isEqualTo("1.00 kB")

    }

    @Test

    fun `Rounding mode`() {

        // The rounding mode used for formatting should be ROUND_HALF_UP.

        val result = formatter.format(1006, BytesFormatter.UseCase.FileSize)

        assertThat(result).isEqualTo("1.01 kB") // Ensure rounding mode is effective

    }

    @Test

    fun `Grouping separator`() {

        // Grouping separators should not be used in the formatted output.

        val result = formatter.format(Long.MAX_VALUE, BytesFormatter.UseCase.FileSize)

        assertThat(result).isEqualTo("9223 PB")

    }

    @Test

    fun `Format with units`() {

        // Verify that the `formatWithUnits` method correctly formats the given bytes with the

        // specified units.

        val resultByte = formatter.formatWithUnits(0, BytesFormatter.UseCase.FileSize)

        assertThat(resultByte).isEqualTo(BytesFormatter.Result("0", "byte"))

        val resultKb = formatter.formatWithUnits(1000, BytesFormatter.UseCase.FileSize)

        assertThat(resultKb).isEqualTo(BytesFormatter.Result("1.00", "kB"))

        val resultMb = formatter.formatWithUnits(479_999_999, BytesFormatter.UseCase.FileSize)

        assertThat(resultMb).isEqualTo(BytesFormatter.Result("480", "MB"))

        val resultGb = formatter.formatWithUnits(20_100_000_000, BytesFormatter.UseCase.FileSize)

        assertThat(resultGb).isEqualTo(BytesFormatter.Result("20.10", "GB"))

        val resultTb =

            formatter.formatWithUnits(300_100_000_000_000, BytesFormatter.UseCase.FileSize)

        assertThat(resultTb).isEqualTo(BytesFormatter.Result("300", "TB"))

        val resultPb =

            formatter.formatWithUnits(1000_000_000_000_000, BytesFormatter.UseCase.FileSize)

        assertThat(resultPb).isEqualTo(BytesFormatter.Result("1.00", "PB"))

    }

}